Crows sure as hell know what a shotgun is. I have lots of crows on my land. Crows will keep a safe distance from me of about 40 yards. It I have a shotgun in my hands that distance instantly increases greatly and sometimes they just leave.
PS
I do not kill animals anymore. The joy of such left me. I have no problem with ethical hunters. My neighbor does hunt my land and we eat the venison. It is delicious.
I forgot to add that I will kill vermin with no emotion. It is just housekeeping on my land.